You just spun up a Hetzner box. Or a DigitalOcean droplet. Or a Vultr instance. You got an IP address. You started building.
But that IP had a life before you. The previous tenant might have been running a spam relay, an open proxy, a phishing site, or a botnet C2 node. They're gone — but the blacklist entries, the reputation damage, and the abuse reports follow the IP, not the person.
Your app's transactional emails go to spam. Signup confirmations, password resets, invoice receipts — sent via your VPS's SMTP or through an API that resolves to your IP. If that IP is on Spamhaus SBL, Gmail and Outlook will junk or reject the email. Your users think your app is broken.
Your webhooks get flagged or dropped. Third-party services that receive webhooks from your server check source IP reputation. A dirty IP means higher latency, more retries, or silent drops. Stripe and payment processors are especially aggressive about IP scoring.
API rate limiting and CAPTCHA walls. Services like GitHub, Cloudflare, and Google apply stricter rate limits and CAPTCHA challenges to IPs from blocks with bad reputation. You'll see more 429s and CAPTCHA pages than a clean IP would.
Your monitoring looks fine. That's the worst part. Your app works. Your tests pass. But 30% of your password reset emails are in spam and you don't know because your test accounts are on the same machine. Users just think "this app doesn't send emails" and leave.
Find your VPS IP: curl ifconfig.me
Enter it in the scanner below. We check all 254 IPs in your /24 block against 10 major blacklists and show you exactly who your neighbors are.
If the report shows SBL listings or a high blacklist count — request a new IP from your provider before you deploy. It's free and takes 5 minutes. Much cheaper than debugging deliverability issues in production.
| Provider | How to get a new IP | Cost |
|---|---|---|
| Hetzner | Delete and recreate the server. Or request via support ticket. | Free |
| DigitalOcean | Destroy droplet and create new one. Floating IP also works. | Free |
| Vultr | Destroy and recreate instance. New IP assigned automatically. | Free |
| Linode (Akamai) | Delete and recreate. Or open a support ticket to swap. | Free |
| AWS EC2 | Release Elastic IP and allocate new one. | Free (if attached) |
| Google Cloud | Release external IP, assign new ephemeral. | Free |
The key insight: do this before you configure DNS, deploy your app, or set up SSL. It takes 60 seconds to scan and 5 minutes to swap. It takes weeks to diagnose a deliverability problem in production.
If you're locked to an IP (long-running server, DNS propagation constraints, etc.):
Route email through an ESP. Don't send from your VPS directly. Use SendGrid, Postmark, or SES for transactional email. They send from their own dedicated IPs, bypassing your VPS's reputation entirely. This is the right architecture regardless — but it's essential if your VPS IP is dirty.
Check if YOU are blacklisted. If your specific IP (not just a neighbor) is on a blacklist, you can request delisting. Spamhaus SBL requires a manual request. SpamCop and Barracuda auto-expire. See our blacklist guide for the full process.
See your neighborhood before you deploy. Free, 60 seconds.